Types of Sun Star Flowers

A relative newcomer on the American houseplant and gardening scene, sun star (Ornithogalum dubium) gets its common name from the appearance of its bright, yellow to orange flowers held in clusters atop a sturdy stem. Native to South Africa, it's a common houseplant and cut flower in Europe. Its other common names are orange everlasting, orange star of Bethlehem and yellow chincherinchee. It is a member of the Hyacinth family, grows from a bulb and is hardy in U.S. Department of Agriculture plant hardiness zones 7 through 10. A number of cultivars exist, including a white-flowered form.

Ornithogalums

Sun star belongs to a group of about 120 species of Ornithogalum from southern Europe, western Asia and Africa. Ornithogalums have a cluster of strap-shaped leaves that emerge from the bulbs, and their flower stalks hold about 15 star-shaped or cup-shaped flowers, which are usually white. Sun star is one of the few ornithogalums with a brightly colored flower. Israeli nurseries introduced the sun star to wide horticultural use. Sun star is valued for its long-lasting flowers, both on the plant and as a cut flower. It has a vase life of three weeks or longer and can bloom up to three months as a potted plant.

Cultivars

Cultivars of Ornithogalum dubium usually have more compact growth forms than the wild species. They also have brighter flower colors lacking the darker central area of the parent plants' flowers, which is an adaptation for beetle pollination. "Orange Star" is a somewhat dwarf plant developed for container use, and so are "Fire Star," with deep-orange flowers, and "Orange Star Improved." Yellow flowers with green centers are featured on "Namib Sun." "Namib Sunrise" has orange flowers with no darkened center. In 2000, the U.S. National Arboretum released new cultivars developed from crossing Ornithogalum dubium with other species. Bred specifically for growing as potted plants, they combine short stature with larger flowers and more flowers per cluster than some other varieties. Examples include "Chesapeake Blaze," which has bright orange flowers, "Chesapeake Sunburst," which has bright, yellow flowers, and "Chesapeake Sunset," which displays deep-orange blooms.

Garden Cultivation

Sun star prefers a well-drained, sunny garden location. The proper bulb depth is 3 inches below the soil surface. Plant new bulbs in fall in climates with mild winters because the bulbs root and grow during cool temperatures. When the leaves emerge from the ground, water the plants thoroughly, but let the soil dry partially between watering sessions. Sun star bulbs produce five to eight glossy, dark-green leaves in a rosette pattern, with one or more 5- to 7-inch tall flower stalks emerging amid the leaves. Each stalk bears up to 20 flowers. The flowers give long-lasting color to garden areas such as rockeries and raised beds, where you can enjoy the blooms close-up and the bulbs receive good drainage. Let the foliage die back naturally after the blooming period because the bulbs undergo summer dormancy. Withhold water during the dormant period. Sometimes dormancy extends more than one season.

Container Plants

Dwarf cultivars are well-suited for planting in containers. Plant several sun star bulbs per container for a showy display. Three bulbs can fit in a 4-inch pot and five bulbs in a 5-inch pot, with bulbs placed about 1/4 inch below the soil surface. Use a well-draining, soilless potting mix. Keep the soil evenly moist but not soggy during the growing season because dry soil damages the plants' delicate roots. The plants grow best in temperatures between 65 and 75 degrees Fahrenheit, with temperatures above 90 degrees Fahrenheit bringing on dormancy.

Propagation

Sun star forms bulblets around the mother bulb. Propagation is usually done by separating bulblets and planting them individually. Sun star also grows from seeds. The seeds are very fine and dustlike. In fall, plant seeds thinly on a well-draining, soilless potting mix, and cover them with a thin layer of builder's sand. Keep the soil moist but not soggy. The seeds should germinate after two weeks. Sun star plants are susceptible to the Ornithogalum mosaic virus, which is spread by aphids as they feed on plants. Some plants are propagated commercially through tissue culture to produce virus-free plants.

About the Author

Cathryn Chaney has worked as a gardening writer since 2002. Her horticultural experience working in the nursery industry informs her garden articles, especially those dealing with arid landscaping and drought-tolerant gardening. Chaney also writes poetry, which has appears in "Woman's World" magazine and elsewhere. Chaney graduated from the University of Arizona in 1992 with a Bachelor of Arts in English.